This invention pertains to a means for transporting large numbers of plant trays. In particular, this invention relates to a novel conveyor for transporting plant trays on cable conveyors powered by a motor to move the plant trays throughout and in and out of a greenhouse.
It is common in the nursery business to use greenhouses for germinating and growing plants. Typically, plants are planted as seeds or cuttings in 11 inch by 22 inch plastic flats. Growing of plants in greenhouses often requires frequent movement of plants from one location to another, such as from the potting shed to the germinating greenhouse, and from one area of a particular greenhouse to another to accommodate sunlight demands of the growing foliage.
A majority of greenhouses employ benches to provide a platform for laying out plants and keep the stock level elevated above the floor. Benches are typically constructed of steel, wood, plastic, or concrete frames with galvanized expanded metal, turkey wire, or special bench fabrics spread across the top. Galvanized expanded metal or other bench surfaces allow water to drain from the plants during frequent watering.
Methods currently used by greenhouses to transfer plants include the use of portable conveyors. The conveyors are typically in multiple sections with each section being ten to twelve feet long. One section, the drive section, is motorized and quite heavy. The other conveyor sections connect to the drive section through a gear mechanism at each junction. The conveyor is typically configured with numerous sections in place and sections are removed and the conveyor shortened as the benches are filled with plants.
The time and effort required to lay out and connect the sections of the conveyor and then remove sections as benches are filled is so substantial that most greenhouse operators have found that this is not acceptable. Most greenhouses have found that it is easier and more efficient to let people carry the flats. One person can typically only carry one or two flats at a time. Therefore, there is typically a lot of labor involved in moving plants around in a greenhouse, and multiple trips must be made up and down the aisles to distribute plants.
It is also known to support numerous plant trays on extended beams which stretch from inside a greenhouse to outside a greenhouse. Commercial nurseries have such facilities in order to move thousands of potted plants, supported on trays, out of the greenhouses into the natural sunlight and exposed to the rain and ambient environment. When and as the weather dictates, the trays are moved along the beams and returned to the protection of the greenhouses and, to this end, a side wall of each greenhouse is apertured to accommodate the beams thereinto.
These prior transport systems have numerous disadvantages. For example, typical plant conveyors known in the art are bulky, heavy, and expensive.
Other transport systems in the prior art include U.S. Pat. No. 4,628,631 and U.S. Pat. No. 4,547,992 which teach a cable driven system, but this is for carrying plants on hangers to a watering station.
U.S. Pat. No. 4,876,967 teaches a transporter for plant trays where the trays have rollers which ride on beams. Here, the first tray has a motor to pull a string of the wheeled trays.
U.S. Pat. No. 4,837,971 teaches a transport system in which moveable tables are provided on which plants in containers have been placed. The legs of the table have wheels that rest on rails.
U.S. Pat. No. 4,930,253 teaches a transport system in which channels filled with water float plant trays. Wires are used to support the trays. Here, a large and heavy, separate conveyor system is used.
Finally, in U.S. Pat. No. 5,974,733, a greenhouse conveyor system is taught which uses manual wheeled carts.
The present invention, uses relatively small diameter cables as the xe2x80x9cbeltxe2x80x9d onto which the plant trays ride. The use of such cables has numerous advantages which will be discussed in detail below.
The present invention is for a system for conveying plant trays in a greenhouse. The system has continuous conveyors, each in the form of a cable having cable ends spliced together and adapted to support and convey in an upright condition plant trays through the greenhouse, the continuous conveyor having an upper plant transport portion and a lower cable return portion. The system has first end and second end pulleys to receive the continuous conveyors and a motor attached to the first end pulleys to drive the continuous conveyor, whereby, the system is capable of transporting the plant trays through the greenhouse on the continuous conveyors from the first end pulleys to the second end pulleys.
Accordingly, it is an object of the present invention to provide an apparatus for conveying plant trays in a greenhouse that overcomes the disadvantages of prior art means to convey plant trays through a greenhouse.
It is another object of the present invention to provide an apparatus for conveying plant trays in a greenhouse that produces a minimal shadow such that plants below and adjacent the apparatus receive maximum sunlight without substantial shadows.
It is yet another object of the present invention to provide an apparatus for conveying plant trays in a greenhouse that produces a minimal shadow such that plants below and adjacent the apparatus receive maximum water spray without substantial deflection of the water by the apparatus.
It is a further object of the present invention to provide an apparatus for conveying plant trays in a greenhouse that is inexpensive to purchase and to operate.
It is another object of the present invention to provide an apparatus for conveying plant trays in a greenhouse that is easy to customize.
It is still another object of the present invention to provide an apparatus for conveying plant trays in a greenhouse that has minimal complexity.
It is another object of the present invention to provide an apparatus for conveying plant trays in a greenhouse that is easy and relatively inexpensive to install.
It is yet another object of the present invention to provide an apparatus for conveying plant trays in a greenhouse that may be easily upgraded or expanded to meet differing need of a user.
It is a further object of the present invention to provide an apparatus for conveying plant trays in a greenhouse that is flexible to allow easy customized installations using standard system assemblies.
It is a still further object of the present invention to provide an apparatus for conveying plant trays in a greenhouse that uses cables that may are adjustable to provide an appropriate amount of tension.
Other objects of the present invention, as well as the novel features thereof, will become more apparent by reference to the following description, taken in conjunction with the following drawings.